Almost seventy years after the failure of the first atomic cargo ship, the United States is once again studying the use of small modular nuclear reactors to power merchant ships.

Written by Douglas Avila

Published on 31/05/2026 at 13:59

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Almost seventy years after the world’s first atomic cargo ship became a commercial failure and was retired, the United States has returned to studying the movement of merchant ships with small nuclear reactors, betting that the technology that buried the idea in the past can now resurrect it.

The story begins with a beautiful and failed ship. In the 1960s, the United States launched the NS Savannah, the first cargo ship powered by atomic energy, a white and elegant engineering marvel made to showcase the peaceful use of the atom. It sailed, enchanted, but never broke even, it was too expensive to operate and was retired. The idea of a commercial nuclear ship seemed to have died there.

Now it is back on the table. The American maritime administration opened a formal request for information in May to develop a commercially viable concept of a merchant ship powered by a small modular nuclear reactor, the so-called SMR. It is a clear sign that the government wants to seriously test if the technology has matured enough to succeed where it failed half a century ago.

Why resurrect a buried idea

The motivation behind this has a name, decarbonization. Maritime transport moves most of the planet’s trade and burns an enormous amount of heavy, polluting fuel. Finding a way to move giant ships without emitting carbon has become an obsession for the industry, and few technologies deliver as much energy without burning anything as nuclear. An atomic ship emits no smoke and doesn’t need fuel tanks.

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What a ship without refueling means

The practical advantage of a nuclear ship is hard to overstate. A reactor can operate for years without a fuel change, meaning the ship crosses entire oceans without ever stopping to refuel. Add to that the total absence of emissions during operation, and you have a vessel that completely changes the logic of long-distance transport, with almost unlimited autonomy and minimal carbon footprint.

For long and constant routes, like those connecting continents, this profile is almost perfect. The ship does not depend on volatile fuel prices, does not face the problem of refueling in distant ports, and does not contribute to the pollution that currently weighs on the sector. It’s the kind of proposal that makes any logistics planner stop to think, even knowing the enormous obstacles ahead.

Bow of the merchant ship powered by nuclear energy — A reactor can operate for years, giving the ship autonomy to cross oceans without refueling.

The obstacles that sank the dream before

It would be naive to think that this time it’s just success. The challenges of a commercial nuclear ship are immense and go far beyond engineering. There’s the issue of safety, because a floating reactor needs extra protection against accidents and the risk of falling into the wrong hands. There’s regulation, because many ports around the world simply do not accept receiving a ship powered by an atom. And there’s the initial cost, which remains very high even with modern reactors.

It’s worth remembering that the nuclear ship is not exactly an absolute novelty at sea. Russia has been operating for decades a fleet of icebreakers powered by reactors, giants that pave the way through the frozen Arctic and prove, in practice, that the technology works at sea. The difference is that these ships are state-owned, funded without the obligation to break even like a common business. The leap that the United States is now studying is precisely to transform this proven capability into something commercially viable, a cargo ship that competes in the market, and not just a state feat. This is where the real difficulty lies, and also the real revolution, if the numbers ever add up.

These were, to a large extent, the same walls that the Savannah could not overcome. The difference is that today’s climate urgency changes the calculation, because now there is enormous pressure to find clean alternatives to fossil fuel, and this may give the nuclear idea a chance it didn’t have in the 1960s. What was experimental luxury can become strategic necessity.

White atomic ship anchored in bay — Safety, port regulation, and cost are the same walls that sank the idea decades ago.

The second chance of an atomic ship

I imagine if in a few years we will see silent cargo ships crossing the oceans powered by reactors the size of a container, without releasing a single column of smoke. It would be the late fulfillment of a promise made almost seventy years ago, when the Savannah glided through the water as a symbol of a future that did not arrive on time.

For now, it is just a study, a request for information that may or may not become reality. But the simple fact that the idea is returning with seriousness already says a lot about the moment we live in, where the search for clean energy is so urgent that it’s worth digging up even the dreams that the past had declared dead. Sometimes an idea was just waiting for the right technology to be reborn, and perhaps, after almost seventy years, its time is finally now.

Would you board a ship powered by a nuclear reactor with peace of mind, or does the idea still leave you with some hesitation?

Almost seventy years after the failure of the first atomic cargo ship, the United States is once again studying the use of small modular nuclear reactors to power merchant ships.